Metallurgical process and products



' fining.

Patented July 2 0, 1937 7 7 2,087,719 v METALLURGICAL PROC SS AND PRODUCTS Albert Grobstein, Washington, .No Drawing. Application December 10, 1929,

v .,Serial No. 413,141. Renewed August 1, 1936 t l 16 Claims. (oi. 75-122):

This invention relates to av process for the extraction of chromium and .phosphorus from their compounds and the novel products resulting therefrom.

I have discovered that chromium and phos-' J phorus may be' extracted from native chromite and phosphatic materialsby a simple reduction process which effects large economies in manua facture of steels and other products utilizing these elements.

Chromium has long been known as adifficul element to reduce and the usual reductionby car.- bon in the presence of ferrous materials results in a high carbon product that needs further re- Non-carbonaceous reducing agents such as silicon and aluminum have been resorted to in order to avoid carbon contamination, but these are expensive and add materially to the cost.

I have found that carbon can be used as a reducing agent and still obtain a low-carbon product if smelting. of chromite ore is done in the presence of phosphorus or phosphatic rock. The phosphorus combines with the iron-"chromium base to exclude the carbon, thus forming a ferro-chromium-phosphorus alloy low in carbon.

This ferro-chromium-phosphorus may be used directly as an alloying addition in making chro- V mium steel containing phosphorus or may be treated with fresh amounts of raw chromite to form low phosphorus-ferro-chromium alloy, together with other compounds of phosphorus.

I prefer to smelt in a suitable furnace a mm ture of chromite ore, phosphatic rock, iron ore, (or iron scrap), silicious material (such as quartz), lime and carbon. By suitably proportioning the acids and bases according to the practice usual in the manufacture of ferro-phosphorus from phosphatic rock, I obtain a product containing chromium, iron and phosphorus, the iron and chromium predominating. I may use this alloy in a number of ways, or I may treat it further to extract the phosphorus. For example, I may blow the molten ferro-chromium-phosphorus in a basic converter, recovering ferro-chromium alloy and phosphatic slag, the latter suitable for use in fertilizer production. Or I may treat the crude alloy of iron-chromium-phosphorus in a basic open hearth and after a preliminary low temperature oxidation-for phosphorus removal, utilize the iron and'chromium remaining as a charge for chromium steel, diluting the same with iron as desired, either before or after the phosphorus extraction.

By my process, I extract chromium and phosphorus from their native compounds by a single smelting and avoidfthe-heretofore usual carbon contamination. All of thisresultsin economies of production of iron-chromium alloysychromium alloy steels, and phosphoric materials used in'the' industries. As will be. understood, vaporized phosphorus and phosphoruscompounds maybe recovered as usual incidents of the process.

If desired, other low carbon ferro-allo'ys and corresponding steels may be'prepared by myproo ess. Examples of these are ferro tungsten, ferromolybdenum f erro-vanadium, ferro nickel, ferrouranium, ferro-manganese, ferro-tantalum, ferrozirconium, ferro-titanium, etc.

aforesaid process or by known conventional processes and particularly the iron-chromium-phosphorus alloy may be used as separateentities to make cast and wrought articles for corrosion ing reducible materials containing iron, chromium and phosphorus and reducing the-same with a carbonaceous reducing agent, the phosphorus being present insufficient amount to preventa large accession of carbon in the alloy.

2. A product obtained according to claim 1' comprising a heat resistant and corrosion resistdients carbon from trace to 1%, iron and chromium totalling from '75 to 99%, and phosphorus from above .5% to 25%, the phosphorus repressing carbide formation in the alloy. v

3. The process of making low carbon alloy iron and steel which comprises smelting an oxygencontaining compound of the group consisting of chromium, tungsten, molybdenum and vanadium, with an additional material containing a substantialamount of combined phosphorus under carbonaceous reducing conditions and refining the product.

4. The process of making an iron-chromium alloy low in carbon which comprises mixing chro mite ore with phosphatic material and smelting the mass with a carbonaceous reducing agent.

. The various alloys disclosed herein made by theant iron base alloy containing as essential ingre- I 5. The process of making low-carbon ironchromium alloys which comprises reducing chromite ore with carbon in the presence of a sub- 6. The process of making low carbon iron chromium alloys which comprises treating chromite ore and ferruginous materials with a reducing agent in the presence of a large amount of phosphorus and then treating the product with an oxidizing agent. i r

7. The steps in ,theprocess of making low carbon iron-chromium alloys which comprise forming a charge containing chromite ore, phosphate. rock, and siliceous material and reducing the with iron totalling from up to 99% of the same with carbon.

8. A low carbon alloy having high resistance to oxidation consisting of iron and chromium totalling from about 79 to about 95%, and'phosphorus from about 5 to about 21%.. V.

9. An iron-chromium-phosphorus alloy containing as essential ingredients iron and chromium totalling from.75 to 99% and phosphorus fromabove 0.5 to 25%, the carbon content of the alloy being from trace to-1%.

10. An alloy containing less than l. .0%-ca r-- bon and containingiron, phosphorus, and at least one element of thergroup consisting of the met als chromium, tungsten, molybdenum and vanadium; the element of the group being present in essential amount totalling withth-e iron from 75% up to 99% of the alloy, and the phosphorus beingjpresentin an amount frcm over 0.5%,,t0 25%.

' a basic converter 5- 11. The process which comprises smelting phosphatic material-and a compound of the group consisting of chromium, tungsten, molybdenum and vanadium, the smelting being carchromium totalling about to'9'7% and phosphorus from about 3 to 20%.

13. As a new article of manufacture, a ferroalloy containing phosphorus from above .5% up to 25%,,and anelement of the group consisting of chromium, tungsten, molybdenum and vanadium, such element and ironbeing present in commercial ferro-alloy proportions and together alloy, the carbon content being less than 2.5%.

14. The process of making an iron-chromium alloy .low in carbon which comprises smelting chromite ore and a: substantial amount of an added phosphatic material with a reducing agent. 15."I'he' process of making an iron-chromium alloy which comprises reducing a, charge 'containing a phosphorus compound and a chromiumcompound to produce ag,-low carbon iron-phos-.

phorus-chromium alloy andblowing the alloy. in

16. The process of makin an iron alloy which comprises smelting a charge containingferruginous'material and a compound of the group consistingof chromium, tungsten, molybdenum and vanadium with a carbonaceous reducing agent and sufiicient phosphatic material to produce alow carbon alloy.

ALBERT eaons'rnin. 

